import pandas as pd
import numpy as np
data = pd.DataFrame({'m':[1,2,3,4,5],'n':[6,7,8,9,0]})
print(data.info())
 
# data['m'] = data['m'].apply(str)
# data['n'] = data['n'].apply(str)
 
data = data.applymap(str)
print(data.info())